import java.util.Scanner;

/*
 *@Student 张策
 */
public class Text {
    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        String or=scanner.nextLine();
        while (!or.equals("Y")&&!or.equals("N")){
            System.out.println("请重新输入");
            or=scanner.nextLine();
        }
    }
}
